Weird. I checked in on my cube today and found the fuse all melted, still worked though. Then this thread shows up in my "Show new replies to your posts."
I had the same thing happen to my cube, was working fine, came back a couple of hours later and the fuse was smoked, cooked the main board pads. I had to solder an external wired fuse holder in to get it working (it actually cooked holes through the fiberglass main board).
I doubt it is caused by an over supply, that should just blow the fuse. In my case I suspect a faulty connection that caused the fuse holder to over heat.